Malicious PDF — malware analysis report

Static analysis result for SHA-256 581a96a640890648…

MALICIOUS

PDF

74.8 KB Created: 2021-04-22 09:36:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: 3fdf800f3e405e733668bc6ea2dd3a95 SHA-1: 7ab7dcfbdf90c22c20f9ee1712abacfea0d088ea SHA-256: 581a96a640890648db0b40a027cbe98da98fe2dbdc376e9408952a95ee0451dd
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically indicating phishing and trojan activity. The document body, though heavily obfuscated, contains references to external URLs and the authoring application 'wkhtmltopdf', suggesting it was generated programmatically. The presence of numerous embedded URLs, many pointing to disposable or unknown domains, further supports a phishing or malicious content delivery scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://www.enwidth.com/sites/default/files/webform/resumes/zozagosetimof.pdf In PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/zavemazawutojene.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13471650610.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/lolavojirubopikumu.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/tarutemivejumariwara.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/zolevijovexoneda.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/kuvusuwube.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/mamak.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=what+are+heaven%2527s+gates+calledPDF link annotation
    • https://gradfutures.princeton.edu/system/files/webform/48950823745.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/68382108709.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/lezedatabamivija.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/42655509772.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e6fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6FB 5308 bytes
SHA-256: 3ca4f90275bca6f3d0791a74ae7ea63b3cf89ee3bb4720b519e14907f36de7d3
font_01_sfnt_off0000f91b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF91B 11036 bytes
SHA-256: b324af07b63e0984ccf55cf813052aed67a4613567f471946b7ce5964d758405

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